Resin composition for reflecting plate

ABSTRACT

The present invention relates to a resin composition for reflector plates containing 30 to 95% by weight of a semi-aromatic polyamide having the ratio of aromatic monomers to all the monomer components being 20% by mole or more, and 5 to 70% by weight of potassium titanate fiber and/or wollastonite. Additionally, the present invention relates to a resin composition for reflector plates used for an ultraviolet-ray generating source, comprising a thermoplastic resin and at least one inorganic compound selected from the group consisting of fibrous and flaky inorganic compounds capable of reflecting ultraviolet rays as well as visible light.

TECHNICAL FIELD

The present invention relates to a resin composition for reflectorplates that is suitably used for emission devices such as a lightemission diode (hereafter, referred to as “LED”).

BACKGROUND ART

LEDs are emission apparatuses which are produced by mounting an emissiondevice on a reflector plate (substrate) and sealing it with epoxy resinor the like, and that have a variety of preferred characteristics suchas being readily incorporated into various instruments due to beingsmall and lightweight, having a very long life on account of beingstrong against vibration and repetition of ON/OFF, and exhibiting clearcoloring and particularly excellent visibility, as well as having arelatively small amount of electricity to be consumed. Of these LEDs, awhite LED fitted with an ultraviolet light emitting device and aphosphor, which emits white light by ultraviolet rays generated by theultraviolet light emitting device, has received great attention as lightsources for a back light of a liquid crystal display screen for acellular phone, a computer, a television and the like, a headlight of anautomobile and an instrument panel, lighting equipment, and the like.

An LED reflector plate used for such emission apparatuses generallyrequires good reflection performance that reflects light or ultravioletrays emitted by an emission device at a high efficiency. In addition,the LED reflector plate needs high dimensional precision because the LEDreflector plate like an emission device is a fine part of from about 1to about 2 mm, and also needs an excellent mechanical strength onaccount of a possible decrease in reflection performance thereof evenfor a small distortion, and further a high heat resistance due to beingexposed to a high temperature by means of soldering and the like.

Conventionally, the reflector plates of LEDs include, for example, areflector plate made by applying plating and coating to a resin moldedarticle. The reflector plate, while acceptably offering practical use inreflection performance, has disadvantages of being difficult touniformly apply plating to the whole, tending to be deviated fromdimensional precision, and having a high rate of defectives, on accountof a very fine article as mentioned above. Furthermore, mechanicalstrength and heat resistance thereof, when considering a long life of anLED, is not sufficiently satisfied.

As such, there is proposed, for example, as a resin composition forreflector plates a resin composition produced by blending withfiberglass a melt processed polyester such as an aromatic polyester andan aromatic polyester amide and further, as appropriate, blendingtitanium oxide (Japanese Examined Patent Application Publication No.06-38520). This resin composition is good in heat resistance anddimensional stability to some extent, but has disadvantages of beinginsufficient in the degree of whiteness, and being low in lightreflection factor. According to the above publication, althoughpotassium titanate fibers and wollastonite are cited as mixableinorganic fibers in addition to fiberglass as well, inorganic fibersthereof in combination with a melt processed polyester cannot obtain asufficient light reflection factor.

Further, proposed are a resin composition containing therein 10 to 40%by weight of an aromatic polyester, 15 to 55% by weight of a polyamide,15 to 45% by weight of a polycarbonate and 10 to 30% by weight oftitanium oxide (Japanese Unexamined Patent Application Publication No.59-113049), a resin composition made of 60 to 95% by weight of apolyamide (nylon 46) and 5 to 40% by weight of titanium oxide (JapaneseUnexamined Patent Application Publication No. 02-288274), a resincomposition made by blending matrix resin of a polyester and a polyamidewith 10 to 50% by weight of titanium oxide and 0.3 to 30% by weight of amodified polyolefin (Japanese Unexamined Patent Application PublicationNo. 03-84060), and the like. These resin compositions, however, providethe disadvantages of large molding shrinkage factor and linear expansioncoefficient, and bad dimensional stability specifically on account ofthe linear expansion coefficient upon a high temperature load.Furthermore, they cannot sufficiently satisfy the light reflectionfactor and light-screening factor.

In other words, resin compositions for conventional reflector plateshave a level of satisfying some physical properties that are needed asthe reflector plate, but pause problems of the other physical propertiesbeing not capable of satisfaction.

Accordingly, taking into consideration the above-described conventionalproblems, it is an object of the present invention to provide a resincomposition for reflector plates that satisfies desired, variousphysical properties at a high level and can be suitably used as areflector plate.

Moreover, in addition to these problems, use of an LED fitted with anultraviolet light emitting device cannot provide sufficient brightnesseven when any of the above-described LED reflector plates are used,leading to the problem of lowering visibility. Hence, as light sourcesof a back light of a liquid crystal display screen for a cellular phone,an instrument panel for an automobile, and the like, the LEDs fittedwith the ultraviolet light emitting device are unsuitable. In addition,neither the mechanical strength nor the heat resistance of the reflectorplates can reach a sufficiently satisfactory level; the use of a longperiod of time results in possible distortion.

Conventionally, in order to primarily improve mechanical strength andheat resistance as well as flame resistance, Japanese Unexamined PatentApplication Publication No. 07-242810 has proposed as a reflector platea resin composition produced by blending a thermoplastic resin such asan aromatic polycarbonate with titanium oxide and potassium titanatefibers. Nonetheless, a reflector plate made of the material utilizespotassium titanate fibers for the purpose of mainly improving mechanicalstrength and heat resistance as well as flame resistance and essentiallyrequires a combination with titanium oxide, and thus the application ofthe reflector plate to a white LED having an ultraviolet light emittingdevice leads to insufficient brightness and is incapable of avoiding adecrease in visibility.

In addition, Japanese Unexamined Patent Application Publication No.62-179780 has disclosed a resin composition made by blending a meltprocessing polyester such as an aromatic polyester or an aromaticpolyester amide with white dyes such as titanium oxide, zinc oxide, zincsulfide, zinc sulfate and white lead, as reflector plate materials, andcontaining therein, as required, a filler such as potassium titanatefibers or fiberglass. However, the above publication neitherspecifically discloses a composition made by blending a polyestersubstantially only with potassium titanate fibers, nor suggests that thecomposition is extremely useful as a reflector plate for a LED equippedwith an ultraviolet light emitting device and a phosphor, which emitslight by ultraviolet rays generated by the ultraviolet light emittingdevice.

On the other hand, a resin composition produced by blending athermoplastic resin with potassium titanate fibers and the like is wellknown besides the above-described publications, and is used as materialsof housing, mechanism parts, sliding parts and the like of electricaland electronic articles, precision machinery, and other machinery. Also,the purpose for blending potassium titanate and the like is only toimprove the mechanical strength.

That is, in prior art, neither use of a composition made by blending athermoplastic resin solely with potassium titanate fibers is carried outas a reflector material for an ultraviolet-ray source, nor specialeffects obtained thereby are known at all.

Thus, it is another object of the present invention to provide a resincomposition for reflector plates that obtains a sufficient reflectionfactor and thus brightness, and which at the same time satisfies theabove-described desired physical properties, even when a composition isemployed for a white LED apparatus fitted with an ultraviolet-rayemission device.

DISCLOSURE OF THE INVENTION

The present inventor, as a result of earnest studies to achieve thefirst above-described object, has successfully obtained a resincomposition suited to material for reflector plates, thus accomplishingthe present invention.

Namely, a first aspect of the present invention relates to a resincomposition for reflector plates characterized by containing 30 to 95%by weight of a semi-aromatic polyamide having the ratio of aromaticmonomers to all the monomer components being 20% by mole or more, and 5to 70% by weight of potassium titanate fiber and/or wollastonite.

In accordance with the first aspect of the present invention, there canbe provided a resin composition, produced by blending therein specifiedinorganic fibers, which do not spoil useful physical properties thesemi-aromatic polyamide has, which satisfy at a high level desiredphysical properties such as the light reflection factor, whiteness,molding processability, mechanical strength, dimensional stability, heatresistance and hygroscopicity, and particularly which are excellent inlight screening and capable of maintaining a high whiteness withoutdiscoloring even though exposed to a high temperature.

While it is known that blending of a synthetic resin with inorganicfibers improves mechanical strength, dimensional stability, heatresistance and the like, the present invention produces these effects aswell as further, by a combination of the aforementioned semi-aromaticpolyamide, potassium titanate fibers and wollastonite, particularlybringing about the excellent effect of light screening being remarkablyhigh.

A resin composition having the excellent physical properties such asstated above of the present invention is useful as a reflector platematerial, especially as an LED reflector plate material.

Furthermore, the present inventor, to achieve the second above-describedobject, has found a novel reflector plate material capable of obtaininga high brightness even when the material is used for a white LEDequipped with an ultraviolet-ray emission device, thus accomplishing thepresent invention.

In other words, a second aspect of the present invention relates to aresin composition for reflector plates used for an ultraviolet-raygenerating source, which is characterized in that the resin compositioncomprises a thermoplastic resin and at least one inorganic compoundselected from the group consisting of fibrous and flaky inorganiccompounds capable of reflecting ultraviolet rays as well as visiblelight.

According to studies of the present inventors, the use of a reflectorplate made of a material produced by blending in a thermoplastic resinat least one inorganic compound selected from the group consisting offibrous and flaky inorganic compounds capable of reflecting ultravioletrays as well as visible light can transmit to a phosphor in a highdensity ultraviolet rays generated by an ultraviolet light emittingdevice, and so it has been found out that generated light of an LEDusing an ultraviolet light emitting device, especially a white LED, canbe made an extremely high brightness and remarkably good visibility. Onthe contrary, a conventionally widely used reflector plate made of aresin composition containing titanium oxide reflects visible light, butabsorbs ultraviolet rays of 420 nm or less, and thus it is estimatedthat the brightness of generated light is not sufficiently high.

In addition, a resin composition relating to the second aspect of thepresent invention satisfies at a high level a variety of characteristicssuch as molding processability, mechanical strength, dimensionalstability, heat resistance, hygroscopicity, and the like, and thereforedoes not lose a long life of a LED.

Now, a resin composition of the second aspect of the present inventioncan be suitably utilized as reflector plates for various ultraviolet-raygenerating sources, specifically for different LEDs fitted with anultraviolet light emitting device and a phosphor, which emits light byultraviolet rays. Of these, the resin composition is more suitably usedfor a white LED.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph indicating the relationship between the wavelength oflight and the reflection factor, of the resin composition (Example 9)according to a second aspect of the present invention.

FIG. 2 is a graph indicating the relationship between the wavelength oflight and the reflection factor, of the resin composition (Example 10)according to the second aspect of the present invention.

FIG. 3 is a graph indicating the relationship between the wavelength oflight and the reflection factor, of the resin composition (Example 11)according to the second aspect of the present invention.

FIG. 4 is a graph indicating the relationship between the wavelength oflight and the reflection factor, of the resin composition (Example 12)according to the second aspect of the present invention.

FIG. 5 is a graph indicating the relationship between the wavelength oflight and the reflection factor, of the conventional resin composition(Comparative Example 7).

FIG. 6 is a graph indicating the relationship between the wavelength oflight and the reflection factor, of the conventional resin composition(Comparative Example 8).

FIG. 7 is a graph indicating the relationship between the wavelength oflight and the reflection factor, of the conventional resin composition(Comparative Example 9).

FIG. 8 is a graph indicating the relationship between the wavelength oflight and the reflection factor, of the conventional resin composition(Comparative Example 10).

BEST MODE FOR CARRYING OUT THE INVENTION

In the first aspect of the present invention, the semi-aromaticpolyamides stand for polyamides containing therein aromatic monomers asmonomer components of a polyamide. For a semi-aromatic polyamide used asa matrix, the aromatic monomers in the monomer components constitutingthe semi-aromatic polyamide are 20% by mole or more, preferably 25% bymole, more preferably from 30 to 60% by mole; the melting point of thesemi-aromatic polyamide is preferably 280° C. or more, more preferablyfrom 280 to 320° C. Here, the molar fractions of the monomers in anaromatic polyamide can be adjusted by setting the ratios of the monomersin polymer material to be specified molar fractions.

The aromatic monomers include, for example, aromatic diamines, aromaticdicarboxylic acids, aromatic aminocarboxylic acids and the like. Thearomatic diamines include, for example, p-phenylenediamine,o-phenylenediamine, m-phenylenediamine, paraxylenediamine,metaxylenediamine and the like. The aromatic dicarboxylic acids include,for example, terephthalic acid, isophthalic acid, phthalic acid,2-methylterephthalic acid, naphthalene dicarboxylic acid and the like.Also, the aromatic aminocarboxylic acids include, for example,p-aminobenzoic acid and the like. Of these, aromatic dicarboxylic acidsare preferable. The aromatic monomers can be used solely or incombination of two or more thereof.

The monomer components exclusive of the aromatic monomers includealiphatic dicarboxylic acids, aliphatic alkylenediamines, alicyclicalkylenediamines, aliphatic aminocarboxylic acids and the like.

The aliphatic dicarboxylic acids include adipic acid, sebacic acid,azelaic acid, dodecanedionic acid and the like. Of these, adipic acid ispreferable. The aliphatic dicarboxylic acids can be used solely or incombination of two or more thereof.

The aliphatic alkylenediamines may be of straight chains or of branchedchains. More specifically, the aliphatic alkylenediamines includeethlenediamine, trimethylenediamine, tetramethylenediamine,pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane,1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane,2-methylpentamethylenediamine, 2-ethyltetrametylenediamine and the like.Of these, hexamethylenediamine, 2-methylpentamethylenediamine and thelike are preferable. The aliphatic alkylenediamines can be used solelyor in combination of two or more thereof.

The alicyclic alkylenediamines include, for example, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane,1,3-bis(aminomethyl)cyclohexane, bis(aminomethyl)cyclohexane,bis(4-aminocyclohexyl)methane,4,4′-diamino-3,3′-dimethyldicyclohexylmethane, isophoronediamine,piperazine and the like. The alicyclic alkylenediamines can be usedsolely or in combination of two or more thereof.

The aliphatic aminocarboxylic acids can include, for example,6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acidand the like; cyclic lactams corresponding to these may be used. Thealiphatic aminocarboxylic acids can be used solely or in combination oftwo or more thereof.

Of these monomer components, aliphatic dicarboxylic acids, aliphaticalkylenediamines and the like are preferable. These monomer componentscan be used solely or in combination of two or more thereof.

Of the aforementioned semi-aromatic polyamides, those containing anaromatic dicarboxylic acid and an aliphatic alkylenediamine, thosecontaining an aromatic dicarboxylic acid, an aliphatic dicarboxylicacid, an aliphatic alkylenediamine and the like are preferable.

Furthermore, even of these semi-aromatic polyamides, the dicarboxylicacids comprising terephthalic acid, and comprising a mixture ofterephthalic acid and isophthalic acid, and comprising a mixture ofterephthalic acid, isophthalic acid and adipic acid are preferable. Inthe two aforementioned mixtures, a mixture having a ratio ofterephthalic acid being 40% by mole or more is particularly preferable.In addition, even of these semi-aromatic polyamides, the aliphaticalkylenediamines comprising hexamethylenediamine and comprising amixture of hexamethylenediamine and 2-methylpentamethylenediamine areparticularly preferable.

Of the semi-aromatic polyamides, as a particularly preferred example, itcan be cited a copolymer produced by copolymerizing 50% by mole ofterephthalic acid, 25% by mole of hexamethylenediamine and 25% by moleof 2-methylpentamethylenediamine.

The appropriate selection of the composition ratios and kinds ofaromatic monomer and other monomer components constituting thesemi-aromatic polyamides can adjust, as required, melting points, glasstransition temperatures and the like.

Additionally, the first aspect of the present invention may use apolyphenylene sulfide along with a semi-aromatic polyamide as a matrixresin of a resin composition. As the polyphenylenesulfides, well knownones all can be used, and linear and crosslinked structures all may beused. For example, crystalline polymers are included that contain ascomposition elements the repeat units denoted by general formulas below:

[wherein Ar represents a 1,4-phenylene group, a 1,3-phenylene group, ora 1,2-phenylene group.]

These polyphenylenesulfides desirably include those containing theaforementioned repeat units as the main components and thus thosecontaining the aforementioned repeat units alone, preferably thosecontaining 80% by mole or more of the repeat units, more preferablythose containing 90% by mole of the repeat units. In a case where thesubstantial total amounts of polyphenylenesulfides are not composed ofthe aforementioned repeat units, the balances can be supplemented withcopolymerizable repeat units, for example, the repeat units below:

[wherein R is an alkyl group, an alkoxy group, a nitro group or aphenylene group.]

In addition, as polyphenylenesulfides, commercially available articlesmay be employed. The commercially available articles include, forexample, Tohpren (trade name, product of Tohpren Co., Ltd.), Ryton(trade name, product of Toray Industries Inc.), Fortron (trade name,product of Polyplastics Co., Ltd.) and the like.

In the first aspect of the present invention, the amount of blending ofa matrix resin component, including cases where the resin componentcomprises a semi-aromatic polyamide alone and comprises a combination ofa semi-aromatic polyamide and a polyphenylenesulfide, is from 30 to 95%by weight based on the total amount of resin composition, preferablyfrom 30 to 90% by weight, more preferably from 40 to 70% by weight. Asthe amount of blending of the resin components deviates from the rangeof 30 to 95% by weight, a resin composition cannot sometimes be obtainedthat satisfies at a high level a variety of physical propertiesnecessary for a reflector plate.

Also, in a case where a semi-aromatic polyamide and apolyphenylenesulfide are use together, although the blending ratios ofthese resins can be, as appropriate, selected, the semi-aromaticpolyamide may be blended so as to be preferably from 40 to 90% by weightbased on the total amount of these resins, more preferably from 50 to80% by weight.

In the first aspect of the present invention, as inorganic fibersblended with a mixture of a semi-aromatic polyamide or the aromaticpolyamide and a polyphenylenesulfide, potassium titanate fibers and/orwollastonite is used.

Potassium titanate fibers are not particularly limited, andconventionally well-known ones are widely used. Examples capable of useinclude 4 potassium titanate fibers, 6 potassium titanate fibers, 8potassium titanate fibers, and the like. The size of potassium titanatefibers is not particularly restricted, but normally an average fiberdiameter is from 0.01 to 1 μm, preferably from 0.1 to 0.5 μm; an averagefiber length is from 1 to 50 μm, preferably from 3 to 30 μm. In thepresent invention, commercial articles are usable as well and, forexample, TISMO (trade name, product of Otsuka Chemical Co., Ltd.,average fiber diameter: 0.2 to 0.5 μm, average fiber length: 5 to 30 μm)and the like can be used.

Wollastonite is an inorganic fiber of calcium metasilicate. The size ofwollastonite is not particularly limited, but normally an average fiberdiameter is from 0.1 to 15 μm, preferably from 2.0 to 7.0 μm; an averagefiber length is from 3 to 180 μm, preferably from 20 to 100 μm. Anaverage aspect ratio is 3 or more, preferably from 3 to 50, morepreferably from 5 to 30.

Wollastonite can suitably use commercially available articles, forexample, including Baistal K101 (trade name, product of Otsuka ChemicalCo., Ltd., average fiber diameter: 2 to 5 μm, average fiber length: 5 to30 μm), NyglosI-10013 (trade name, product of Nyco Corp., average fiberdiameter: 5 to 30 μm, average fiber length: 5 to 30 μm), and the like.

Of these, taking into account the light-screening factor and thewhiteness of an obtained resin composition, potassium titanate fiber ispreferable.

In the first aspect of the present invention, in order to furtherimprove physical properties such as mechanical strength of a resultantresin composition, potassium titanate fiber and wollastonite may besurface treated. Surface treatment follows a well-known process, and canbe carried out using a silane coupling agent, a titanium coupling agent,or the like. Of these, a silane coupling agent is preferable andaminosilane is particularly preferable.

The amount of blending of potassium titanate fiber and/or wollastoniteis normally from 5 to 70% by weight based on the total amount of resincomposition, preferably from 10 to 70% by weight (resin component: 30 to90% by weight), more preferably from 20 to 60% by weight (resincomponent: 40 to 80% by weight). As the amount deviates from the rangeof 5 to 70% by weight, a resin composition that satisfies at a highlevel various physical properties required for a reflector plate cannotbe obtained in some cases.

Furthermore, in the first aspect of the present invention, within therange of not spoiling preferred, various physical properties of a resincomposition, particularly in order to further improve the lightreflection factor, the light-screening factor and the like, titaniumoxide may be blended. In particular, when wollastonite is used as aninorganic fiber, it is preferable to use it in combination with titaniumoxide. Titanium oxide is not particularly limited, and a variety ofcrystalline forms such as the anatase type, the rutile type, and themonoclinic type all can be employed. Although different crystallineforms can be used in combination of two or more types, the rutile typeis preferable that has a high refractive index and is good in lightstability. Also, the shape of titanium oxide is particularly unlimitedas well, diverse shapes such as a particle shape, a fiber shape, and aplate shape (including a flake shape, a scale shape, a mica shape, andthe like) all can be used, and different shapes can also be used incombination of two or more shapes. While the size of titanium oxide isnot particularly restricted, an average size thereof is preferably from0.1 to 0.3 μm in particle diameter. In addition, those that are treatedwith various surface treatment agents may be used. The amount ofblending of titanium oxide is not particularly limited, it is, asappropriate, selected within the range of improving reflectionefficiency as well as not losing preferred physical properties of aresin composition. However, normally, the amount of blending can be fromabout 1 to about 40% by weight (resin component: 30 to 94% by weight,potassium titanate fiber and/or wollastonite: 5 to 69% by weight) basedon the total amount of resin composition, preferably from about 5 toabout 30% by weight (resin component: 30 to 90% by weight, potassiumtitanate fiber and/or wollastonite: 5 to 65% by weight).

A resin composition concerning the first aspect of the presentinvention, within the range of not spoiling preferred physicalproperties thereof, may be blended with a well-known inorganic fiberexclusive of potassium titanate fiber and wollastonite. The inorganicfibers are not particularly limited, for example, being capable ofincluding zinc oxide fiber, sodium titanate fiber, aluminum boratefiber, magnesium borate fiber, magnesium oxide fiber, aluminum silicatefiber, silicon nitride fiber, and the like.

Moreover, a resin composition relating to the first aspect of thepresent invention, within the range of not damaging preferred physicalproperties thereof, may be blended with an antioxidant, a heatstabilizer and the like.

The antioxidants include a phenol-based antioxidant, a phosphorus-basedantioxidant, a sulfur-based antioxidant and the like.

The phenol-based antioxidants include, for example, triethylene glycolbis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediolbis[3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate],pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate],octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate,3,5-di-t-butyl-4-hydroxybenzilphosphonate-diethylester,N,N′-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydroxycinnamide),1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzil) benzene,3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane,and the like. Of these,pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate],N,N′-hexamethylenebis(3,5-di-t-butyl-4-hydro-hydroxycinnamide) arepreferable.

Examples of the phosphorus-based antioxidants include, for example,tris(2,4-di-t-butylphenyl) phosphite,2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphebin6-yl]oxy]-N,N-bis[2-[[2,4,8,10-tetrakis(1,1dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphebin6-yl]oxy]-ethyl]ethanamin,bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphate, and thelike. Of these,2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphebin6-yl]oxy]-N,N-bis[2-[[2,4,8,10-tetrakis(1,1dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphebin6-yl]oxy]-ethyl]ethanaminis preferable.

Examples of the sulfur-based antioxidants include, for example,2,2-thio-diethlenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],tetrakis[methylene-3-(dodecylthio)propionate]methane, and the like.

These antioxidants can be used solely or in combination of two or morethereof.

Furthermore, a resin composition according to the first aspect of thepresent invention, within the range of not damaging preferred physicalproperties thereof, can be blended with one, or two or more of a varietyof additives that have been used for synthetic resins as usual. Theadditives include, for example, inorganic fillers such as talc, silica,and zinc oxide (including a tetrapod shape), a fire retardant, aplasticizer, a nucleating agent, a pigment, a dye, a releasing agent, anultraviolet absorber, and the like.

A resin composition of the first aspect of the present invention can beproduced by melting and blending an aromatic polyamide with wollastoniteand/or potassium titanate fiber and further, as required, otheradditives in accordance with a well-known process. Melting and blendingcan utilize all well-known melting and blending apparatuses such as atwin screw extruder.

A resin composition of the first aspect of the present invention can bemolded to give a molded article (i.e., reflector plate) suitable for avariety of applications by means of a well-known resin molding processsuch as the injection molding process, the compression molding process,the extrusion process, or the like.

A reflector plate thus obtained can suitably be used, for example, as areflector plate for emission apparatuses including emission apparatusesand the like used for various electrical and electronic parts, a keylessentry system of an automobile, lighting in a refrigerator, a back lightof a liquid crystal display apparatus, an automobile front panellighting apparatus, a desk lamp, a headlight, a household electricalappliance indicators, optical communication instruments such as aninfrared communication apparatus, a ceiling illumination apparatus,outdoor display apparatuses such as a traffic sign, and the like.

On the other hand, a resin composition for reflector plates of thesecond aspect of the present invention has as the essential components athermoplastic resin and at least one inorganic compound selected fromthe group consisting of fibrous and flaky inorganic compounds capable ofreflecting ultraviolet rays as well as visible light.

The thermoplastic resins can use all well-known ones, for example, beingable to include a semi-aromatic polyamide, an aliphatic polyamide, apolyester, polyethylene terephthalate, polypropylene terephthalate,polybutylene terephthalate, polyethylene naphthalate, a liquidcrystalline polymer, polyethylene, a chlorinated polyethylene,polypropylene, polyisoprene, polybutadiene, polyvinyl chloride,polyvinylidene fluoride, polytetrafluoroethylene, polyacetal,polycarbonate, acryl resin, polystylene, an impact-resistantpolystylene, syndiotactic polystylene, acrylonitrile-styrene resin (ASresin), acrylonitrile-butadiene-styrene resin (ABS resin),methylmathacrylate-butadiene-styrene resin (MBS resin),methylmathacrylate-acrylonitrile-butadiene-styrene resin (MABS resin),acrylonitrile-acrylic rubber-styrene resin (AAS resin),polymethyl(meta)acrylate, polymethylpentene, polyphenylene ether (PPE),a modified polyphenylene ether, polyketone-based resins (polyetherketone, polyether ether ketone, polyether ketone ketone, polyether etherketone ketone, and the like), polyethernitrile, polybenzoimidazole,polyether sulfone, polysulfone, a thermoplastic polyimide, polyetherimide, polyarylate, polyphenylene sulfide, polyphenylene oxide,polyamideimide, polyaromatic resin, and the like.

Of these, a thermoplastic resin that absorbs little visible light and/ora transparent thermoplastic resin is preferable, and further those thatare high in solder heat resistance are preferable. The examples caninclude a semi-aromatic polyamide, an aliphatic polyamide, a liquidcrystalline polymer, syndiotactic polystylene, polybutyleneterephthalate, polyethylene terephthalate, polyethylene naphthalate,polyacetal, polymethylpentene, and the like. Here, absorption of visiblelight being little specifically means that the appearance of the resinexhibits white even though dark or pale.

Of these resins, semi-aromatic polyamides (Japanese Unexamined PatentApplication Publication Nos. 2001-279093, 2001-106908, 2000-273300,2000-219809, 2000-186142, 2000-80270, 11-263840, 10-338746, 09-279020,09-279018, 08-34850, 07-228694, 05-32870, etc.), a liquid crystallinepolymer, syndiotactic polystylene, and the like are particularlypreferable.

In addition, the thermoplastic resins can be used solely or incombination of two or more thereof.

The amount of blending of a thermoplastic resin in a reflector platematerial according to the second aspect of the present invention is notparticularly limited, and may be selected, as required, from a widerange in accordance with various conditions such as the kind ofthermoplastic resin itself, the kinds of combination-used visible andultraviolet reflecting inorganic compounds, the kind of illuminant towhich a resulting reflector plate is applied, and the like. However,taking into consideration the fact that the brightness of reflectionlight is further improved, the amount of blending is from 30 to 95% byweight based on the total amount of material of the present invention,preferably from 40 to 90% by weight.

In the second aspect of the present invention, fibrous and flakyinorganic compounds capable of reflecting ultraviolet rays as well asvisible light stand for inorganic compounds capable of reflectingultraviolet rays as well as visible light when being blended anddispersed in a thermoplastic resin. The inorganic compounds can usefibrous and/or flaky (plate-like) material, for example, includingcompounds containing potassium titanate and the like. A compoundcontaining potassium titanate has characteristics of improving themechanical strength and heat resistance of a thermoplastic resin to be amatrix and not losing the dimensional precision and moldingprocessability.

The compounds containing potassium titanate can utilize all well-knowncompounds that contain potassium titanate and are fibrous or flaky. Theexamples can include potassium titanate fiber, flaky potassium titanate,flaky lithium potassium titanate, flaky potassium magnesium titanate,and the like.

The potassium titanate fibers can use those as for the above-describedfirst aspect.

The flaky lithium potassium titanate is a well-known compound containingpotassium titanate in which some of the potassium atoms of potassiumtitanate are replaced by lithium atoms. Examples are disclosed inJapanese Unexamined Patent Application Publication Nos. 03-285819,2000-344520, etc.

The flaky potassium magnesium titanate is a well-known compoundcontaining potassium titanate in which some of the potassium atoms ofpotassium titanate are replaced by magnesium atoms. Examples aredisclosed in Japanese Unexamined Patent Application Publication Nos.03-285819, 05-221795, 2000-230168, etc.

Further, a compound containing flaky potassium titanate of a hollanditestructure expressed by a general formula K_(x)Ti₈O₁₆ (x=1.0 to 2.0)(Japanese Unexamined Patent Application Publication No. 62-105925), acompound containing flaky potassium titanate of a hollandite typestructure expressed by a general formula (K_(x-y)H_(y))Ti₈O₁₆ (x=1.0 to1.3, 0<y≦0.7) (Japanese Unexamined Patent Application Publication No.02-92822), etc. can also be used as compounds containing potassiumtitanate.

The fibrous and flaky inorganic compounds capable of reflectingultraviolet rays as well as visible light can be used singly or incombination of two or more thereof.

Additionally, in the second aspect of the present invention, in order tofurther improve physical properties such as the mechanical strength of areflector plate material obtained, surface treatment may be applied to avisible light and ultraviolet ray reflecting inorganic compound. Surfacetreatment may be conducted in accordance with a well-known process, anda silane coupling agent, a titanium coupling agent, and the like can beused. Of these, a silane coupling agent is preferable and aminosilane isparticularly preferable.

The amount of blending of the fibrous and flaky inorganic compoundcapable of reflecting ultraviolet rays as well as visible light is notparticularly limited, and may be selected, as required, from a widerange in accordance with various conditions such as the kind ofcombination-used thermoplastic resin, the kinds of visible andultraviolet reflecting inorganic compounds themselves, the kind ofilluminant to which a resulting reflector plate is applied, and thelike. However, taking into consideration the fact that the brightness ofreflection light is further improved, the amount of blending is normallyfrom 5 to 70% by weight based on the total amount of resin compositionaccording to the second embodiment of the present invention, preferablyfrom 10 to 60% by weight.

A resin composition for reflector plates according to the second aspectof the present invention, within the range of not spoiling preferredcharacteristics thereof, can be blended with the antioxidant, heatstabilizer and the like as described above.

A resin composition for reflector plates according to the second aspectof the present invention, within the range of not spoiling preferredcharacteristics thereof, can be further blended with one, or two or moreof a variety of additives conventionally used for synthetic resins. Theadditives can include, for example, fibrous inorganic fillers such aswollastonite and fiberglass, powdered inorganic fillers such as silicaand talc, a dye, an antioxidant, an antistat, a mold release, alubricant, a heat stabilizer, a drip inhibitor, a fire retardant, anultraviolet absorber, a light stabilizer, a light-screening agent, ametal inactivating agent, an age resistor, a plasticizer, an impactstrength improving agent, a compatibilizing agent, a viscositycontrolling agent, an anti-foaming agent, a leveling agent, an organicsolvent, and the like.

This additive is preferably set to be in a proportion of less than 10%by weight based on the total amount of ingredients of resin.

A resin composition for reflector plates according to the second aspectof the present invention can be produced by blending or kneading asynthetic resin, an inorganic compound capable of reflecting ultravioletrays as well as visible light, and further, as necessary, otheradditives by means of well-known means. For example, pellets of a resincompositions of reflector plates concerning the second aspect of thepresent invention can be manufactured by blending or kneading powder,beads, flakes or each ingredient of pellet shapes using a kneader andthe like such as an extruder such as a single extruder or a twinextruder, a Banbury mixer, a pressurizing kneader, a twin roll, and thelike.

Also, a resin composition for reflector plates according to the secondaspect of the present invention is formed via a well-known resin moldingprocess such as the injection molding process, the compression moldingprocess, or the extrusion process to be able to make a reflector plateof an arbitrary shape.

Reflector plates comprising a resin composition of the second aspect ofthe present invention is useful for reflector plates of emissionapparatuses equipped with a variety of ultraviolet ray sources. Theoptical sources can include, for example, an LED fitted with anultraviolet light emitting device and a phosphor that produces color byreceiving ultraviolet rays, an ultraviolet lamp, a mercury lamp, acold-cathode tube, a fluorescent lamp, an incandescent lamp, and thelike. Furthermore, they are applied to illumination apparatuses with theemission apparatus and the like as well. Of these, the reflector plateis useful for an LED, particularly for a white LED.

In addition, an ultraviolet ray generating source having a reflectorplate comprising a resin composition of the second aspect of the presentinvention can be used for applications as for conventional ultravioletray generating sources.

Examples of the Applications Include:

-   communication applications such as LANs, facsimile, fiber    communication and the like;-   advertisement and information applications such as interior and    exterior display plates, cubic displays, accessories, and the like;-   measurement and control applications such as vending machines,    automatic doors, diverse sensors, light sources for color    measurement, and the like;-   automobile applications such as meters within interior panels,    indicators, high mounting stop lamps, tail lamps, marker lights, and    the like;-   office appliance and OA applications such as electronic photo light    sources, CD reading light sources, printers, scanners, and the like;-   traffic and transportation applications: vehicle light devices,    signal signs, and the like.-   crime prevention and disaster protection applications such as    emergency lights, smoke detectors, gas leak detectors, and the like;-   forestry and fishery applications: light traps, fishing lures,    growth promoting light sources, and the like;-   medical applications such as medical testing instruments, support    systems, sterilizing apparatuses, and the like;-   household appliance applications such as VTRs, DVDs, stereos,    televisions, air conditioners, indicators of household appliances,    level meters, and the like; and-   back light optical sources of various liquid crystal display screens    of personal computers, cellular phones, liquid crystal televisions,    and the like, etc.    As discussed above, according to a resin composition of the second    aspect of the present invention, when a reflector plate is used for    an emission apparatus such as a white LED using ultraviolet rays as    a light source, it can well reflect visible light and ultraviolet    rays, thus obtaining sufficient brightness.

EXAMPLES

First, resin compositions according to the first aspect of the presentinvention will specifically be set forth in terms of Examples andComparative Examples. Additionally, synthetic resins and inorganicfibers used in the present

Examples and the Comparative Examples are specified as follows:

[Synthetic Resins]

Semi-aromatic polyamide A: a semi-aromatic polyamide (trade name “AmodelA4000”, product of DuPont) produced by polymerizinghexamethylenediamine, terephthalic acid and adipic acid, in the ratio of50% by mole to 32% by mole to 18% by mole, respectively.

Semi-aromatic polyamide B: a semi-aromatic polyamide (trade name “ZytelHTN501”, product of DuPont, melting point 305° C., glass transitiontemperature 125° C.) produced by polymerizing2-methylpentamethylenediamine, hexamethylenediamine and terephthalicacid in the ratio of 25% by mole, 25% by mole and 50% by mole,respectively.

Polyphenylsulfide: (trade name “Ryton M2888”, product of TorayIndustries Inc., hereafter referred to as “PPS”).

Aromatic polyester: (trade name “VECTRA C950”, product of PolyplasticsCo., Ltd., hereafter referred to as “LCP”).

[Inorganic Fibers]

Wollastonite: (trade name “Baistal K101,” product of Otsuka ChemicalCo., Ltd., average fiber diameter 2 to 5 μm, average fiber length 20 to30 μm).

Potassium titanate fiber: (trade name “TISMO D101,” product of OtsukaChemical Co., Ltd., average fiber length 10 to 20 μm, average fiberdiameter 0.3 to 0.6 μm).

Powder titanium oxide: (trade name “JR-405,” product of TaycaCorporation, average particle diameter 0.21 μm).

Chopped glass fiber: (trade name “ECS 03T 249/PL,” product of NipponElectric Glass Co., Ltd., hereafter called “GF”).

Examples 1 to 8 and Comparative Examples 1 to 6

In the blending ratios (% by weight) indicated in Table 5 below, pelletsof a resin composition of the first aspect of the present invention wereproduced by charging a semi-aromatic polyamide or a semi-aromaticpolyamide and PPS into the main hopper of a twin-screw kneadingextruder, after melt kneading at 330° C., adding thereto potassiumtitanate fiber or wollastonite and further titanium oxide from the sidefeeder, and then melt kneading and extruding the mixture.

The pellets thus obtained of a resin composition concerning the firstaspect of the present invention were introduced into an injectionmolding machine (trade name “JS75,” product of The Japan Steel Works,Ltd., cylinder temperature 330° C.) equipped with a mold for making aJIS test piece (mold temperature 130° C.) to conduct injection molding,thereby producing various JIS test pieces, with subjecting the testpieces to the following performance tests.

(1) Tensile strength and tensile break elongation: measured inaccordance with JIS K7113.

(2) Bending strength and bending elastic modulus: measured in accordancewith JIS K7271.

(3) Impact value by a IZOD with a notch: evaluated using No.1 test piecein accordance with JIS K7110.

(4) HDT (heat resistance test): Heat distortion temperature (HDT, ° C.)was measured according to JIS K7207 when a bending stress 1.82 MPa wasapplied.

(5) Coefficient of linear expansion: measured at 20 to 130° C. using aTAM120 thermal machine analysis apparatus (trade name “SSC5200HDisk-station,” product of Seiko Instruments Inc.). The pulling outdirection was denoted by MD and the vertical direction thereof denotedby TD. In order to evaluate the index of anisotropy, the linearexpansion coefficient ratio of TD to MD (TD/MD) was indicated.

(6) Flow rate (Q value): measured using a higher type flow tester onExamples 1 to 8 and Comparative Examples 1 to 4 at 330° C.×9.8 MPa, onExample 9 at 290° C.×9.8 MPa, and on Comparative Example 10 at 310°C.×9.8 MPa, each having a residual heat time of 360 seconds, an orrispore diameter of 1 mm and a thickness of 10 mm.

(7) Water absorption degree: measured in accordance with JIS K7209.

(8) Hunter whiteness: measured using a color difference meter fromNippon Denshoku Industries Co., Ltd. Also, the evaluations were denotedby ⊚ for whiteness of 93 or more, by ∘ of less than 93 and 91 or more,by Δ of less than 91 and 89 or more, by x of less than 89 and 85 ormore, and by xx of 85 or less.

(9) Heat resistance discoloring test: The heat resistance discoloringtest was carried out in an oven in air at 180° C.×2 hours and thewhiteness was measured as in (8).

(10) Light ray transmission: A sample that was made a film of 100 μmthick with a vacuum pressing machine was measured by means of arecording spectrophotometer U-3000 model from Hitachi, Ltd. andtransmittances thereof using 460 nm, 530 nm and 630 nm were recorded.

The evaluations were indicated with ⊚ for a transmittance of 0%, with ∘of below 3% and 0% or more, with Δ of below 5% and 3% or more, and withx of 5% or more.

These results are tabulated in Table 1. TABLE 1 Example ComparativeExample 1 2 3 4 5 6 7 8 1 2 3 4 5 6 Semi-aromatic polyamide A 50 50 5035 — — — — 50 35 — — — — Semi-aromatic polyamide B — — — — 50 50 50 35 —15 50 35 — — PPS — — — 15 — — — 15 — — — 15 50 — LCP — — — — — — — — — —— — — 50 Potassium titanate fiber 50 30 — — 50 30 — — — — — — — —Wollastonite — — 30 30 — — 30 30 — — — — 30 30 GF — — — — — — — — 30 3030 30 — — Titanium oxide — 20 20 20 — 20 20 20 20 20 20 20 20 20 Tensilestrength (MPa) 183 176 136 117 191 171 130 116 132 119 130 121 131 91Tensile break elongation 2.5 2.7 2.4 2.1 2.4 2.6 2.1 1.8 2.4 2 2.2 1.82.1 1.4 (%) Bending strength (MPa) 339 257 217 161 331 278 236 166 195149 200 155 174 141 Bending elastic modulus 15.3 12.0 10.7 11.0 16.513.1 11.5 12.7 10.3 10.1 11 10.7 14.5 14.3 (GPa) IZOD impact value (J/m)49 45 39 35 42 48 39 34 47 40 45 39 37 20 HDT(° C.) 285 281 280 270 250245 245 242 285 275 250 248 232 223 Linear MD 1.5 2.3 2.5 2.4 1.1 1.82.0 1.9 2.1 2.0 1.5 1.6 1.9 2.1 expansion TD 5.0 4.7 4.6 4.6 3.5 3.3 3.23.2 5.7 5.7 4.0 4.1 3.2 3.0 coefficient TD/MD 3.3 2.0 1.8 1.9 3.2 1.81.6 1.7 2.7 2.9 2.7 2.6 1.7 1.4 (×10⁻⁵/K) Q value (×10⁻² cm³) 2.4 1.21.1 4.9 9.6 8.2 8.1 14 0.5 2.9 5.5 9.2 15.3 3.2 Water absorption degree0.2 0.2 0.19 0.14 0.1 0.1 0.09 0.07 0.21 0.15 0.15 0.1 0.02 0.03 (%)Hunter whiteness After molding ◯ ◯ ⊚ ◯ ◯ ⊚ ⊚ ⊚ Δ Δ ◯ ◯ XX XX After heatΔ Δ ◯ Δ ⊚ ⊚ ⊚ ◯ X X ◯ ◯ XX XX resistance discoloring test Light ray (460nm) ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Δ Δ Δ Δ ⊚ ⊚ transmission (530 nm) ⊚ ⊚ ◯ ◯ ⊚ ⊚ ◯ ◯ XX X X ◯ ⊚ (%) (630 nm) ⊚ ⊚ ◯ ◯ ⊚ ⊚ ◯ ◯ X X X X ◯ ⊚

FIG. 1 shows that resin compositions of the first aspect of the presentinvention satisfy physical properties the reflector plate requires athigh levels for the mechanical strength, heat resistance, linearexpansion coefficient (dimensional stability), flowability (moldingprocessability), whiteness, heat resistance discoloring, and light raytransmission. In particular, the light ray transmission is greatlylowered as compared with those of Comparative Examples 1 to 4 usingfiberglass. Further, also, because Comparative Examples 5 and 6 usingother heat resistance resins such as PPS, LCP and the like are extremelyinferior in whiteness due to the color order of base resins themselves,it is clear that compositions indicated in the present Examples areexcellent as reflector plates.

Next, resin compositions of the second aspect of the present inventionwill specifically be described in terms of Examples and ComparativeExamples. In addition, thermoplastic resins used in the present Examplesand fibrous or flaky inorganic compounds capable of reflectingultraviolet rays as well as visible light are specified as follows:

[Thermoplastic Resins]

Semi-aromatic polyamide: a semi-aromatic polyamide (trade name “ZytelHTN501,” product of DuPont, melting point 305° C., glass transitiontemperature 125° C.) produced by polymerizing2-methylpentamethylenediamine, hexamethylenediamine and terephthalicacid in the ratio of 25% by mole, 25% by mole and 50% by mole,respectively.

Liquid crystal polymer: (trade name “VECTRA C950RX,” product ofPolyplastics Co., Ltd.).

[Inorganic Fillers]

Potassium titanate fiber: (trade name “TISMO D101,” product of OtsukaChemical Co., Ltd., fiber length 10 to 20 μm, fiber diameter 0.3 to 0.6μm).

Litium potassium titanate: composition: K_(0.8)Ti_(1.73)Li_(0.27)O₄,maximum diameter 3 to 5 82 m, minimum diameter 3 to 50 μm, thickness 0.5to 2 μm.

Potassium magnesium titanate: (trade name “TERRACESS PS,” product ofOtsuka Chemical Co., Ltd., maximum diameter 3 to 5 μm, minimum diameter3 to 5 μm, thickness 0.5 to 2 μm).

Powder titanium oxide: rutile type titanium oxide (trade name“JR-405,”product of Tayca Corporation, average particle diameter 0.21μm).

Fiberglass: (trade name “Chopped Strand ECS03T249/PL,” product of DenkiKagaku Kogyo K.K. average fiber length 3 mm, average fiber diameter 13μm).

Examples 9 to 12 and Comparative Examples 7 to 10

Based on the blending ratios (% by weight) shown in Tables 2 and 3,pellets of reflector plate material of the present invention wereproduced by charging a thermoplastic resin into the main hopper of atwin-screw kneading extruder, after melt kneading, adding thereto aninorganic filler from the side feeder, and then melt kneading andextruding the mixture. In addition, the melt kneading temperatures ofthermoplastic resins in a twin-screw kneading extruder were set to be330° C. for Examples 9 to 11 and Comparative Examples 7 to 9, and 310°C. for Example 12 and Comparative Example 10.

The pellets thus obtained of resin compositions for reflector platesaccording to the second aspect of the present invention were chargedinto an injection molding machine (trade name: JS75, product of TheJapan Steel Works, Ltd., cylinder temperature 330° C.) fitted with a JIStest piece preparing mold (mold temperature 130° C.=Examples 9 to 11 andComparative Examples 7 to 9, mold temperature 120° C.=Example 12 andComparative Example 10) to carry out injection molding, therebyproducing each kind of JIS test pieces, with subjecting the test piecesto the following performance test of (11) in addition to theabove-described performance tests of (1) to (5) and (7) and (8).

Additionally, Examples 9 to 11 and Comparative Examples 7 to 9 weresubjected to 130° C. of the mold temperature and 330° C. of the cylindertemperature of the injection molding machine, and Example 12 andComparative Example 10 subjected to 120° C. of the mold temperature and310° C. of the cylinder temperature of the injection molding machine.

The results are tabulated in Tables 2 and 3.

(11) Reflection factor: The pellets obtained in the Examples and theComparative Examples were injection molded as for the above to producetest pieces of 90 mm×50 mm×3.2 mm. The 380 nm reflection factor (%) ofthis test piece was measured with a visible and ultravioletspectrophotometer (product of Hitachi, Ltd., magnetic spectrophotometerU-3000 model). For reference magnesium oxide was used. From themeasurements thus obtained, 60% or more of the reflection factor wasdecided to be ⊚, 45% to less than 60% to be ∘, 30% to less than 45% tobe Δ, 15% to less than 30% to be x, and less than 15% to be xx.

Also, using the measuring method of the aforementioned reflectionfactor, the relationship between the wavelength and the reflectionfactor, of light, was determined. The results are shown in FIGS. 1 to 8.In FIGS. 1 to 8, the ordinate shows the reflection factor (%) of lightand the abscissa the wavelength (nm) of light. TABLE 2 [Example] 9 10 1112 Semi-aromatic polyamide 70 70 70 Liquid crystal polymer 70 Potassiumtitanate fiber 30 30 Potassium lithium titanate 30 Magnesium potassiumtitanate 30 Fiberglass Rutile type titanium oxide Tensile strength (MPa)180 113 112 184 Tensile break elongation (%) 3.7 3.8 3.7 4.7 Bendingstrength (MPa) 270 152 148 204 Bending elastic modulus (GPa) 9.1 6.8 6.413.0 IZOD impact value (J/m) 38 34 35 160 HDT(° C.) 253 228 223 228Linear expansion MD 2.2 3.8 3.9 1.2 coefficient TD 5.6 3.9 4.1 4.2(×10⁻⁵/K) TD/MD 2.5 1.0 1.1 3.5 Q value (×10⁻² cm³) 0.17 0.18 0.17 0.04Hunter whiteness ⊚ ◯ ⊚ ◯ Reflection factor (380 nm, %) ⊚ ⊚ ⊚ ◯

TABLE 3 [Comparative Example] 7 8 9 10 Semi-aromatic polyamide 70 70 70Liquid crystal polymer 70 Potassium titanate fiber 20 Potassium lithiumtitanate Magnesium potassium titanate Fiberglass 20 20 Rutile typetitanium oxide 30 10 10 10 Tensile strength (MPa) 80 132 123 101 Tensilebreak elongation (%) 1.7 2.3 2.3 1.9 Bending strength (MPa) 110 237 161141 Bending elastic modulus (GPa) 3.2 8.7 7.1 10.3 IZOD impact value(J/m) 24 44 29 80 HDT(° C.) 178 243 254 220 Linear expansion MD 5.8 2.82.7 1.0 coefficient TD 5.9 6.1 6.7 4.5 (×10⁻⁵/K) TD/MD 1.0 2.2 2.5 4.5 Qvalue (×10⁻² cm³) 0.18 0.17 0.17 0.04 Hunter whiteness ⊚ ⊚ ⊚ ◯Reflection factor (380 nm, %) XX XX XX XX

Tables 2 and 3 clearly indicate that resin compositions of reflectorplates according to the second aspect of the present invention meet at ahigh level a variety of characteristics such as mechanical strength,dimensional stability, heat resistance, and hygroscopicity.

In addition, FIGS. 1 to 8 show that resin compositions of reflectorplates according to the second aspect of the present invention reflectultraviolet rays, particularly ultraviolet rays of from 360 nm to 400nm, at high efficiency (FIGS. 1 to 4). More specifically, the reflectorplate of Example 9 containing potassium titanate fiber is remarkablyhigh in reflection factor of ultraviolet rays (FIG. 1), whereas the case(Comparative Example 7) only containing rutile type titanium oxide andthe case (Comparative Example 8) containing both potassium titanatefiber and rutile type titanium oxide are insufficient in reflectionfactor of ultraviolet rays (FIGS. 5 and 6), that is, the degrees ofreflection of ultraviolet rays are clearly extraordinarily low.

These results have proved that a resin composition for reflector platesconcerning the second aspect of the present invention efficientlyreflects ultraviolet rays as well as visible light and is suitablematerial as a resin composition for reflector plates when an ultravioletray is a light source.

1-9. (canceled) 10: A resin composition for reflector plates comprising30 to 95% by weight of a semi-aromatic polyamide having the ratio ofaromatic monomers to all the monomer components being at least 20% bymole, and 5 to 70% by weight of potassium titanate fiber orwollastonite, or both. 11: The resin composition for reflector platesaccording to claim 10, wherein said semi-aromatic polyamide comprises asemi-aromatic polyamide containing, as monomer components, an aromaticdicarboxylic acid and an aliphatic alkylenediamine. 12: The resincomposition for reflector plates according to claim 11, wherein saidsemi-aromatic polyamide comprises a semi-aromatic polyamide furthercontaining, as a monomer component, an aliphatic dicarboxylic acid. 13:A resin composition for reflector plates used for an ultraviolet-raygenerating source, comprising a thermoplastic resin and at least oneinorganic compound selected from the group consisting of fibrous andflaky inorganic compounds capable of reflecting ultraviolet rays as wellas visible light. 14: The resin composition for reflector platesaccording to claim 13, wherein the fibrous and flaky inorganic compoundcapable of reflecting ultraviolet rays as well as visible light is acompound containing potassium titanate. 15: The resin composition forreflector plates according to claim 14, wherein the compound containingpotassium titanate comprises at least one selected from the groupconsisting of potassium titanate fiber, flaky lithium potassiumtitanate, and flaky potassium magnesium titanate. 16: The resincomposition for reflector plates according to claim 13, wherein thethermoplastic resin comprises at least one thermoplastic resin thatabsorbs little visible light or transparent thermoplastic resins, orboth. 17: The resin composition for reflector plates according to claim16, wherein the thermoplastic resin that absorbs little visible light orthe transparent thermoplastic resin, or both, comprises at least oneselected from the group consisting of semi-aromatic polyamides,aliphatic polyamides, liquid crystal polymers, syndiotactic polystyrene,polybutylene terephthalate, polyethylene terephthalate, polyethylenenaphthalate, polymethylpentene, and polyacetal. 18: The resincomposition for reflector plates according to claim 13, comprising 30 to95% by weight of a thermoplastic resin and 5 to 70% by weight of aninorganic compound capable of reflecting ultraviolet rays as well asvisible light. 19: The resin composition for reflector plates accordingto claim 14, wherein the thermoplastic resin comprises at least onethermoplastic resin that absorbs little visible light or transparentthermoplastic resins, or both. 20: The resin composition for reflectorplates according to claim 15, wherein the thermoplastic resin comprisesat least one thermoplastic resin that absorbs little visible light ortransparent thermoplastic resins, or both. 21: The resin composition forreflector plates according to claim 14, comprising 30 to 95% by weightof a thermoplastic resin and 5 to 70% by weight of an inorganic compoundcapable of reflecting ultraviolet rays as well as visible light. 22: Theresin composition for reflector plates according to claim 15, comprising30 to 95% by weight of a thermoplastic resin and 5 to 70% by weight ofan inorganic compound capable of reflecting ultraviolet rays as well asvisible light. 23: The resin composition for reflector plates accordingto claim 16, comprising 30 to 95% by weight of a thermoplastic resin and5 to 70% by weight of an inorganic compound capable of reflectingultraviolet rays as well as visible light. 24: The resin composition forreflector plates according to claim 17, comprising 30 to 95% by weightof a thermoplastic resin and 5 to 70% by weight of an inorganic compoundcapable of reflecting ultraviolet rays as well as visible light. 25: Theresin composition for reflector plates according to claim 19, whereinthe thermoplastic resin that absorbs little visible light or thetransparent thermoplastic resin comprises at least one selected from thegroup consisting of semi-aromatic polyamides, aliphatic polyamides,liquid crystal polymers, syndiotactic polystyrene, polybutyleneterephthalate, polyethylene terephthalate, polyethylene naphthalate,polymethylpentene, and polyacetal. 26: The resin composition forreflector plates according to claim 20, wherein the thermoplastic resinthat absorbs little visible light or the transparent thermoplastic resincomprises at least one selected from the group consisting ofsemi-aromatic polyamides, aliphatic polyamides, liquid crystal polymers,syndiotactic polystyrene, polybutylene terephthalate, polyethyleneterephthalate, polyethylene naphthalate, polymethylpentene, andpolyacetal.